An occluded vessel in the body of a patient is cleared by severing the occluding matter (e.g., the intima of a blood vessel), for example by inflating a balloon (i.e., angioplasty), applying a cryogenic fluid, exposing the vessel to laser or an electric potential, and removing matter by a rotating blade (rotablator). This severing action initiates a healing process in the vessel, which causes production of new tissue cells, thereby once again constricting the passage through the vessel. The growth of tissue cells occurs over a period of a few months following the surgery. In order to keep the passageway open for a longer period of time, and prevent tissue cell to grow as a result of healing, a rigid thin wall tube whose wall is in form of wire mesh (i.e., stent) is mounted in the severed portion of the vessel, within the vessel.
Methods and systems for maneuvering the stent catheter to the desired location within the vessel, after severing the vessel are known in art. For example, a marker band is attached to the catheter close to the stent, thereby enabling the physician to navigate the catheter by viewing the marker band in a real-time X-ray image of the vessel. In another case, the physician can view a representation of the position and orientation of the stent on the real-time X-ray image, according to position and orientation data acquired by a medical positioning system (MPS) sensor, attached to the catheter close to the stent.
U.S. Pat. No. 5,928,248 issued to Acker and entitled “Guided Deployment of Stents”, is directed to an apparatus for applying a stent in a tubular structure of a patient. The apparatus includes a catheter, a hub, a pressure control device, a balloon, a stent, a probe field transducer, a plurality of external field transducers, a field transmitting and receiving device, a computer, an input device and a cathode ray tube. The catheter includes a bore. The hub is affixed to a proximal end of the catheter. The balloon is mounted on a distal end of the catheter. The pressure control device is connected to the balloon through the hub and the bore. The stent is made of a shape memory alloy and is located on the balloon.
The probe field transducer is located within the catheter, at a distal end thereof. The external field transducers are located outside of the patient (e.g., connected to the patient-supporting bed). The field transmitting and receiving device is connected to the external field transducers, the probe field transducer and to the computer. The computer is connected to the cathode ray tube and to the input device.
A user calibrates the field transmitting and receiving device in an external field of reference, by employing the external field transducers. The field transmitting and receiving device together with the computer, determine the position and orientation of the probe field transducer in the external field of reference. The user views the position and orientation of a representation of the stent which is located within a tubular structure of the patient, on the cathode ray tube. When the user determines that the distal end is located at the desired location within the tubular structure, the user expands the stent by operating the pressure control device and inflating the balloon, thereby positioning the stent at the desired location.
U.S. Pat. No. 5,830,222 issued to Makower and entitled “Device, System and Method for Interstitial Transvascular Intervention”, is directed to a method for gaining percutaneous access to a diseased vessel through an adjacent intact vessel. Using this method, it is possible to bypass the diseased vessel, such as a coronary artery, through the intact vessel, such as a cardiac vein. The diseased vessel may include an occlusion that restricts the flow. A guide-catheter is advanced through the vena cava into the coronary sinus, within the right atrium of the heart. A transvascular interstitial surgery (TVIS) guide catheter is inserted through the guide-catheter and advanced through the cardiac vein over a first guidewire, to a desired location adjacent the coronary artery.
The TVIS guide-catheter includes a balloon, a TVIS probe and either or both of active orientation detection means and passive orientation detection means. The TVIS probe is a rigid wire, antenna, light guide or energy guide capable of being inserted in tissue. The passive orientation detection means allow radiographic, fluoroscopic, magnetic or sonographic detection of position and orientation of the TVIS probe. The active orientation detection means is a transmitter. A second guidewire is inserted into the coronary artery adjacent the cardiac vein, wherein the second guidewire includes a small receiver to receive a signal emitted by the active orientation detection means. The second guidewire further includes a wire bundle which is capable to return the signal detected by the receiver, to an operator, thereby enabling the operator to determine the position and location of the TVIS probe.
When the orientation of the TVIS guide-catheter is assured, the balloon is inflated against the wall of the cardiac vein, in order to block the flow, stabilize the TVIS guide-catheter within the cardiac vein and dilate the passageway. The TVIS probe, is then advanced through the wall of the cardiac vein into the coronary artery, thereby bypassing the diseased section of the coronary artery.
U.S. patent Publication No. 20020049375 entitled “Method and Apparatus for Real Time Quantitative Three-Dimensional Image Reconstruction of a Moving Organ and Intra-Body Navigation”, is directed to a system for displaying an image of a lumen of a patient into which a surgical catheter is inserted, while taking into account the movements of the lumen caused by the heart beats of the patient. The system includes the surgical catheter, an imaging catheter, an imaging system, a medical positioning system (MPS), a transmitter, a body MPS sensor, a processor, a plurality of electrocardiogram (ECG) electrodes, an ECG monitor, a database, and a display. The surgical catheter includes a catheter MPS sensor located at a tip thereof. The imaging catheter includes an imaging MPS sensor and an image detector, both located at a tip of the imaging catheter.
The ECG electrodes are attached to the body of the patient and to the ECG monitor. The body MPS sensor is attached to the body of the patient and to the MPS. The processor is coupled with the imaging system, the MPS, the ECG monitor, the database and with the display. The MPS is coupled with the transmitter. During the scanning procedure the MPS is coupled with the imaging MPS sensor. During the surgical procedure the MPS is coupled with the catheter MPS sensor. The imaging system is coupled with the image detector. The imaging MPS sensor and the catheter MPS sensor send a signal respective of the position and orientation of the tip of the imaging catheter and the surgical catheter, respectively, to the MPS.
During the scanning procedure, an operator inserts the imaging catheter into the lumen and advances it therein, while the image detector scans the inner wall of the lumen and transmits detected two-dimensional images to the imaging system. The processor reconstructs a plurality of three-dimensional images according to the two-dimensional images and according to the coordinates of the tip of the imaging catheter determined by the MPS, while the processor associates each three-dimensional image with a respective activity state of the heart of the patient.
During the surgical procedure, the operator inserts the surgical catheter into the lumen and the catheter MPS sensor sends a location signal respective of the position and orientation of the tip of the surgical catheter to the MPS. As the operator moves the surgical catheter within the lumen, the processor determines a sequence of three-dimensional images of the lumen by retrieving data from the database, and according to the current position and orientation of the tip of the surgical catheter and the current activity state of the heart of the patient. The display displays the three-dimensional images in sequence, according to a video signal received from the processor.
U.S. Pat. No. 6,035,856 issued to LaFontaine et al., and entitled “Percutaneous Bypass with Branching Vessel”, is directed to a method for performing a bypass on a first occlusion of a branching vessel of the aorta. A coronary artery which includes the first occlusion, and a branching vessel branch out of the aorta. A standard guide-catheter is advanced through the aorta up to the ostium of the branching vessel. An occlusion forming device is advanced through the guide-catheter into the branching vessel, to produce a second occlusion in the branching vessel. The occlusion device includes an elongate portion and a heated balloon.
The occlusion forming device is removed from the aorta through the guide-catheter and a cutting device is advanced through the guide-catheter proximal to the second occlusion. The cutting device includes an elongate member, a steerable guidewire, a proximal occlusion balloon, a distal balloon, a stent, a cutting blade, a first piece of magnetic material and a transmitter. The cutting blade is located distal to the distal balloon, the first piece of the magnetic material is located between the cutting blade and the distal balloon and the transmitter is located within the distal balloon. The distal balloon is located within the stent. The transmitter emits radio frequency signals.
The wall of the branching vessel is cut by employing the cutting blade. The distal balloon is kept in the expanded position, in order to occlude the branching vessel after the branching vessel has been cut. The severed end of the branching vessel is steered toward a region of the coronary artery distal to the first occlusion, by maneuvering the steerable guidewire or by manipulating the first piece of the magnetic material by a second piece of magnetic material, wherein the second piece of magnetic material is located outside the body of the patient.
The true position and the relative position of the transmitter and thus the position of the severed end of the branching vessel, is determined by employing a triangulation and coordinate mapping system. The triangulation and coordinate mapping system includes three reference electrodes which are located outside the body of the patient. Two of the reference electrodes are located on opposite sides of the heart and the third is located on the back. The three reference electrodes are used to triangulate on the transmitter.
When the severed end of the branching vessel is properly positioned, an aperture is formed in the coronary artery distal to the first occlusion, by employing the cutting blade. The severed end of the branching vessel is inserted into the coronary artery through the aperture and the stent is expanded by inflating the distal balloon, thereby attaching the severed end of the branching vessel to the lumen of the coronary artery.